1. Field of the Invention
This invention relates to a vibratory screed for use in finishing freshly placed concrete pavements.
2. The Prior Art
A variety of screeding devices is disclosed in the prior art. U.S. Pat. No. 4,030,873 (Morrison) discloses a screed device having multiple elongated frame sections with vibratory action imparted by a motor-driven rotating shaft. The screed bars are L-shaped metallic members.
U.S. Pat. No. 3,435,740 (McGall) discloses a screed device having multiple elongated frame sections from which depend rectangular, reciprocating, metallic screed bars, and further having hand winch advancing means.
U.S. Pat. No. 4,249,327 (Allen) discloses a screed device with multiple elongated frame sections, hand winch advancing means and pneumatic vibrators. The front screed bar is an inverted T-shaped metallic member and the rear screed bar is an L-shaped metallic member.
Other screed devices known to those skilled in this art include features such as self-propelled hydraulic winches, adjustable crown or sag means, eccentric weights spaced along a rotating vibrator shaft, and fine grader attachment devices.
Heretofore, screed devices of the type to which the present invention relates have had screed bars with but one useable wearing surface for downwardly engaging the fresh concrete. When that surface is no longer useable due to the abrasive effects of the concrete, the worn screed bar must be removed, discarded and replaced with a new one at significant expense.
The present invention solves this problem by providing a screed device with detachable screed bars which are invertible about their longitudinal axes to provide two useable wearing surfaces. Furthermore, the screed device of the invention combines other advantageous features in a unique manner to provide a highly effective device.